Backlash and wear take-up for gears



Nov. 24, 1936. J. SPENCE. JR 8 BACKLASH AND WEAR TAKE-UP FOR GEARSOriginal Filed May 22, 1930 V w i a VINVENTOR] AWN, mom.

Patented Nov. 24, 1936 UNlTEl) stares PATENT @FFEQE BACKLASH AND WEARTAKE-UP FOR GEARS 454,578. Divided and this application August 1, 1934,Serial No. 737,885

11 Claims.

The present invention relates to an improvement in gears, and has, forits principal object, the provision of means, in a gear or pinion, foreliminating back lash or lost motion in the driving or driven actionthereof, and, further, to provide the gear with a constantly stressedtake-up means for the adjusting for wear, the stress being exertedconstantly in one direction.

This device is divided out of my co-pending United States patentapplication, maturing into Patent No. 1,977,154, dated October 16, 1934,and entitled Camera support.

The present invention is shown in conjunction with a double-disc orsplit gear, in which two spur-gears of like diameter on the pitchcircles and like number of teeth and diametral pitch are connected faceto face and are provided with means whereby they are relatively radiallyrotatable for a portion of an arc, less than the pitch of one tooth andsuch radialmovement is constantly applied and tooth wear is continuallybeing overcome, during operation of the gear.

The foregoing and other features will be noted as the herein descriptionproceeds, and it is obvious that modifications may be made in thestructure of the herein described device without departing from spiritthereof or the scope of the appended claims.

In the drawing,

Fig. 1 is an elevational side view of the gear;

Fig. 2 is a sectional view taken on line 2-2, Fig. 1, looking in thedirection of the arrows;

Fig. 3 is a fragmentary sectional view taken on the line 3-3, Fig. 1,looking in the direction of the arrows;

Fig. 4 is a fragmentary View taken on the line 44, Fig. 1, looking inthe direction of the arrow; and

Fig. 5 is a fragmentary view of Fig. 1, showing the details of the wedgerecess and gibway.

As in Fig. 2, the gear comprises two duplicate gears 46 ll, both mountedin contact assembly on a shaft 48. One of the gears 56 is fixedlymounted to rotate with and on shaft 18 by means of the key 49. The othergear ll is a free gear, that is, it is rotatable on shaft 48, and isheld in its cooperative position adjacent gear 46 by a fixed flange 41'on shaft 43.

As in Fig. 5 the movable gear 41 is provided with a recess 52 cut clearthrough its thickness, such recess including, at its upper end as viewedin Fig. 5, a pin clearance or recess 5|. At the bottom of the recessthere is provided a blind bore 54 in which to seat one end of a coiledspring.

The fixed gear 46 has affixed to its contact face, a driving pin or dog50, Figs. 1, 2 and 4, and when the gears are assembled, as in Fig. 2,for operative function, the pin 5 protrudes into the recess 5! of themovable gear, as shown dotted in Fig. 1. The recess 51 is larger thanthe diameter of the pin 55, so that pin will have desired freedom ofmovement in its association with gear 47.

The gear i'i has two gibways, a and I), cut on opposite sides of therecess 52, as in Fig. 3, to receive and slidably support therein the twoopposed gibs c and d on a movable slide wedge 53, which is operativelymounted for sliding take-up movement in the recess 52, as in Fig. 1.

The wedge has a blind bore e therein, as in Fig. 1, whereby to seat oneend of a coiled spring 54 therein, the other end of said coiled springbeing seated in seat 54 as previously described.

The upper side of the wedge 53, as viewed in Fig. 1, is angled, as at f,with a round nose g on its upper end.

When in operative assembly, as shown in Figs. 1 and 2, it is obviousthat, the spring 54 in compression, exerts a radial pressure upon thewedge 55, outwardly. This pressure causes the wedge or angled face 7 topress upon the side of pin 55, thus tending to cause the two gears tomove in opposite rotative directions under the stress of spring 54, suchstress being constantly exerted.

Thus when the gear herein is about to be meshed with a companion drivingor driven gear, not shown, and the wedge 53 is pushed inward towards theaxis of the gear, to release the stress,

the gears mesh, and wedge 53 is then released.

This causes the gear teeth on gears 45-4? to grip the teeth of themeshed gear firmly preventing back-lash between the meshed gears and asthe teeth wear, the wedge 53 is automatically moved forward sufficientlyto take up such tooth wear.

Due to the lack of play between the meshed gears the noise of running isgreatly reduced.

From the foregoing, it will be noted that the desired action of thegears is accomplished by a sliding wedge which is under constant radialstress and which acts in a radial direction to care for back lash andWear.

It will also be noted that the wedge is irreversible, that is, no amountof pressure by pin 5 upon the wedge slide face f will push the wedge 53backwards, but the small spring 54 can easily move the wedge slideoutwardly.

Having thus described the invention what is claimed is: v

1. An anti-back lash and Wear take up for a gear comprising incombination a pair of gears mounted in side contact with each other, oneof said gears being provided with a radially located gib-way, saidgib-way having one open side which is closed by the other contactinggear, a slide located in said gib-way, said slide having a wedge end,means for constantly stressing the slide radially outwardly and. a pinfixed in the other said gear and projecting into said gib-way andengaging said wedge end.

2. An anti-back lash and wear take up for a gear comprising incombination with a pair of gears mounted in side contact with each otherupon a shaft, one of said gears being fixed to said shaft, the othergear being mounted upon said shaft, one of said gears being providedwith a radially located gib-way, said gib-way having one open side whichis closed by the other contacting gear, a slide encompassed by saidgears in said gib-Way, a wedge end on said slide, means for resilientlyconstantly stressing the slide radially outwardly and a pin fixed uponthe other said gear and projecting into said gib-way and engaging saidwedge end to cause both gears to be stressed radially in oppositedirections.

3. A gear comprising in combination a relatively movable disc includingperipheral teeth and having therein a radial slot with one open face, asecond disc having teeth aligned with the first teeth, said second dischaving movable side contact with the first disc and closing the slot atsaid open face, a pin disposed in one end of said slot and carried bythe second disc, a radially movable member disposed in the slot andhaving at one end an inclined face, said face engaging the pin, andspring means seated in the opposite end of said slot and engaging theopposite end of said member in urging relation.

4. A gear comprising in combination a toothed disc having therein aradial slot which is provided with lateral undercut extensions, arelatively movable mating disc having teeth associated with the firstteeth, a pin disposed in one end of the slot and spaced from the wallthereof, said pin being rigid with the second mentioned disc, a wedgemember slidably mounted in the slot and having offset gibs disposed insaid extensions, said member having at its pointed end an inclined facewhich engages said pin in the space, and a spring urging the oppositeend of said member, said spring being seated in the opposite end of saidslot.

5. A gear comprising in combination a peripherally toothed disc havingtherein a radial slot, said disc having therein and communicating withthe inner end of the slot a bored seat; a second disc having teethcoacting with the first teeth, a pin disposed in the outer end of saidslot and spaced from the wall thereof, said pin being rigid with thesecond mentioned disc; a wedge member slidably mounted in said slot andhaving in its inner end a bored seat, said member having at its outerend an inclined face which engages said pin in the space, and acompressed coil spring having its opposite ends positioned in the boredseats.

6. A gear comprising in combination a pair of discs having coactingperipheral teeth, one of said discs having therein a radial slot whichis expanded at its outer end, said slot having opposed undercut lateralexpansions towards its inner end, said latter disc having therein andcommunicating with the inner end of the slot a bored seat; a pindisposed in the outer end expansion and having a space thereabout, saidpin being fast on the other disc; a wedge slidably mounted in the slot,the inner end of the wedge having therein and axial with the bored seatanother bored seat, said wedge having parallel gibs in said lateralexpansions and the outer or pointed end of the wedge having one of itssides engaging said pin, and a compressed coil spring having itsopposite ends disposed in the bored seats, whereby to constantly urgesaid side against the pin.

'7. In combination, a gear including a toothed disc having a radial slottherein, a shaft whereon said disc is mounted for rotative movement, asecond disc engaging one side of the first disc and being rigid with theshaft, said second disc having teeth normally aligned with the firstteeth, a pin disposed in one end of said slot and having a spacethereabout, said pin being fixed on the relatively rigid disc, a flangealso rigid with said shaft and engaging the opposite side of the movabledisc, a slidable member disposed in said slot and having an inclinedportion extending into said space, and linearly expansible means havingone end disposed in the inner end of said slot, the other end of saidmeans being engaged in urging relation against the inner end of saidmember, said portion being engaged against said pin, whereby toconstantly urge the respective teeth out of the alignment.

8. In combination, a shaft having an annular guide fixed thereto, a gearincluding a toothed disc and having thereon a projection, means attaching said disc to the shaft, said disc forming another guide, asecond disc mounted for rotative movement on said shaft and having itsopposite sides engaged by said guides, teeth carried by the movable discand normally aligned with the first teeth, said movable disc havingtherein a recess and a bore or seat, integral parallel radial tracksarranged to connect with said recess and the bore, said projectionhaving a space thereabout and being positioned in the recess, a radiallymovable member disposed between and cooperating with the tracks, saidmember having an inclined face at one of its ends, said face beingengaged against said pin in the space, and expansible means seated insaid bore and engaging the other end of said member, whereby toconstantly urge the respective teeth out of the alignment.

9. A gear comprising in combination a toothed disc having thereon a pin,a relatively movable toothed disc having therein a radial slot in oneend of which the pinv is disposed so as to provide a space around thepin, said discs being in flatwise engagement and the respective teethbeing normally aligned; a radially movable member disposed in said slotand having on its inner lateral sides opposed gibs, said movable dischaving therein and associated with the slot a gibway for the gibs, saidmember having at one of its ends an inclined face which engages one sideof said pin, the space on the opposite side of said pin being ratherless than a tooth interval, and a compressed spring seated in theopposite end of said slot and engaging the opposite end of said member,so that said face may constantly urge said pin whereby to expand saidteeth to compensate for Wear thereof.

10. A gear comprising in combination a pair of fiat discs havingregistering shaft openings, said discs being relatively fixed andmovable and having normally aligned peripheral teeth the relativelymovable disc having therein an opening which is provided with parallelradially disposed boundary faces, said faces providing parallel innerexpansions adjoining the other disc, said latter disc having fastthereon and disposed in the outer end of the opening a pin, and meansdisposed in said opening and coacting with the pin whereby to constantlyurge the respective teeth out of the alignment, said means including aslidable member, said member having parallel sides which coact with saidfaces, and the inner portions of said sides being expanded and disposedin the expansions of the opening.

11. A gear comprising a peripherally toothed disc having rigid therewitha pin, said disc being relatively fixed and having a fiat side, arelatively movable disc having teeth normally aligned with the firstteeth, said movable disc having therein an elongate radially disposedguide chamber, said fiat side providing the inner boundary of thechamber, the latter having in one end thereof said pin, and a springpressed member slidably disposed substantially in the other end of thechamber and having an inclined urge the respective teeth out of thealignment.

JOHN L. SPENCE, JR.

